I have an animation I'm trying to upload to Sketchfab, which uses some empties to help offset some rotations, etc. The problem is that for some reason, Sketchfab ignores the empties so nothing parented to them moves. Here's what it looks like in sketchfab right now:

you're right! I set it to 60 fps in blender to make it looks smoother, but it looks fine at x0.5 in sketchfab. I'm assuming some interpolation magic is involved to maintain the animation quality at lower speeds.

To maybe make things clearer, we should make the distinction between the model being processed and the model that is viewed in sketchfab viewer.For blend & fbx models, we bake all incoming models using native interpolators at 30 fps. The sketchfab viewer then uses simple linear interpolation over baked frames. To avoid having huge animation data to download, we also remove redundant baked frames during our processing.

So @TheShadyColombian, you should hopefully not have to worry and bake your animation before uploading it, we'll take care of this.The only case where you should have a difference is if you use constant interpolation for which we still have to fix our blender processing pipeline.